The present invention relates to small reliable pumps for delivering at relatively low pressure and low flow rates fluids of diverse types. Applications for such pumps include medical implants, miniature scrubbing systems, chemical analysis of very small samples including liquid chromatography and medical diagnosis.
In the past the delivery of very small portions of a fluid material has, for example, utilized small syringes with a plunger digitally controlled by a motor. Such systems possess a number of disadvantages including the requirement of a substantial sample relative to the possible low flow rates; the ability to pump only a discreet sample without interruption for refilling; and relative bulkiness compared to the small quantities delivered.
Present interest focuses on pumping rates at the level or in the general neighborhood of one or more microliters per minute. Being able to deliver such small quantities controllably and reliably for periods of time is an object for the present invention.